PR_SET_MM_ARG_START allows us to relatively cleanly implement process renaming.
However, it's only available with privileges. Hence, let's try to make use of
it, and if we can't fall back to the traditional way of overriding argv[0].
This removes size restrictions on the process name shown in argv[] at least for
privileged processes.
This reworks get_process_cmdline() quite substantially, fixing the following:
- Fixes:
https://github.com/systemd/systemd/pull/3512/commits/a4e3bf4d7ac2de51191ce136ee9361ba319e106c#r66837630
- The passed max_length is also applied to the "comm" name, if comm_fallback is
set.
- The right thing happens if max_length == 1 is specified
- when the cmdline "foobar" is abbreviated to 6 characters the result is not
"foobar" instead of "foo...".
- trailing whitespace are removed before the ... suffix is appended. The 7
character abbreviation of "foo barz" is hence "foo..." instead of "foo ...".
- leading whitespace are suppressed from the cmdline
- a comprehensive test case is added
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
Introduce a proper enum, and don't pass around string ids anymore. This
simplifies things quite a bit, and makes virtualization detection more
similar to architecture detection.
A number of fields do not apply to all processes, including: there a
processes without a controlling tty, without parent process, without
service, user services or session. To distuingish these cases from the
case where we simply don't have the data, always return ENXIO for them,
while returning ENODATA for the case where we really lack the
information.
Also update the credentials dumping code to show this properly. Fields
that are known but do not apply are now shown as "n/a".
Note that this also changes some of the calls in process-util.c and
cgroup-util.c to return ENXIO for these cases.
Lennart Poettering
Zbigniew Jędrzejewski-Szmek
Davide Cavalca
Thomas Hindoe Paaboel Andersen
Evgeny Vereshchagin
Ronny Chevalier